s390/zcrypt: Support for CCA protected key block version 2

There will come a new CCA keyblock version 2 for protected keys
delivered back to the OS. The difference is only the amount of
available buffer space to be up to 256 bytes for version 2.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>